Even More Bay Bridge Problems: Corrosive Rust Discovered

In what’s becoming a familiar refrain, there are even more problems for the new eastern span of the Bay Bridge. According to a new investigation by the Sacramento Bee’s Charles Piller, this time the problem is rust.

The Sacramento Bee collected rust from two locations on the bridge and had them independently analyzed to confirm that corrosion was occurring. The rust appears on “some of the most vulnerable and integral cable sections and rods” that are crucial to the bridge’s unique self-suspension design.

From the Bee's report:

“Inside one of the chambers, where the suspension cable is attached, the cable strands and rods show rust. Lab tests confirm the rust, alarming independent engineering experts who warn of severe long-term implications. They urge the California Department of Transportation to move quickly to fix the problem.”

In an exclusive KQED Newsroom web extra, Piller explains the bridge’s unique design, and why this newly discovered rust is dangerous.

The bridge was designed with a planned service life of 150 years. If the corrosion caused by the rust worsens, experts believe it will lead to structural damage that would dramatically shorten the intended life of the bridge. The corrosion is also significant because it leaves the rods and cables in question vulnerable to cracks. Those cracks could potentially worsen because of the continual vibration caused by passing trucks and cars. Growing cracks would then “jeopardize the strength of the span’s single main cable,” according to UC Berkeley engineering professor Abolhassan Astaneh-Asl.

In an interview with KQED's Scott Shafer, Piller said he doesn't necessarily think the bridge is in “danger of falling down anytime soon.” But, Piller does have concerns:

“We’re talking about a series of potentially significant structural defects and doubts — uncertainties that haven’t been well examined yet by Caltrans and its advisors. Until those defects and uncertainties are examined carefully … I think everyone in the Bay Area should take the stability of that structure, that $6.5 billion bridge, with some reservation and concern."

According to Piller’s report, the affected portion of the bridge was exposed to more than 21 inches of rain during the bridge’s construction from December 2011 to December 2012, in addition to “mist and humidity from the bay’s marine environment.”

The Sacramento Bee story reports that in recent meetings held to discuss the new problems, Caltrans "acknowledged that some concerns raised by the two independent experts have merit." The report has prompted several elected officials to call for an outside review of the corrosion.

Watch Scott Shafer’s full interview with Charles Piller from Friday’s KQED Newsroom.

KQED NEWSROOM is a weekly news magazine program on television, radio and online. Watch Fridays at 8 p.m. on KQED Public Television 9, listen on Sundays at 6 p.m. on KQED Public Radio 88.5 FM and watch on demand here.